The invention relates to novel powder mixtures, in particular cermet powders, for the surface coating of metal substrates by thermal spraying processes such as plasma spraying or high-velocity flame spraying (HVOF), flame spraying, electric arc spraying, laser spraying or application welding, for example the PTA process.
Such powders comprise at least one finely divided hard material powder such as WC, Cr3C2, TiC, B4C, TiCN, Mo2C, etc., and a finely divided metal or alloy matrix powder. Hard material powder and matrix powder are intensively mixed, usually in the presence of a solution of an organic binder, if appropriate with comilling, atomized, dried, sieved and subsequently heated under a hydrogen-containing atmosphere to remove the organic binder and produce a sintered bond so that relatively large agglomerates having a particle size of from 10 to 100 μm are formed.
DE-B2-1446207 discloses a flame spraying powder which contains metal carbides as hard material and from 10 to 45% of aluminum and nickel as metal.
As matrix metal powders, cobalt- and nickel-containing powders, in particular, have become established in the industry.